Author: Bengtsson, J.
Paper Title Page
MOPPD016 Status of Proof-of-principle Experiment for Coherent Electron Cooling 400
  • I. Pinayev, S.A. Belomestnykh, I. Ben-Zvi, J. Bengtsson, A. Elizarov, A.V. Fedotov, D.M. Gassner, Y. Hao, D. Kayran, V. Litvinenko, G.J. Mahler, W. Meng, T. Roser, B. Sheehy, R. Than, J.E. Tuozzolo, G. Wang, S.D. Webb, V. Yakimenko
    BNL, Upton, Long Island, New York, USA
  • G.I. Bell, D.L. Bruhwiler, V.H. Ranjbar, B.T. Schwartz
    Tech-X, Boulder, Colorado, USA
  • A. Hutton, G.A. Krafft, M. Poelker, R.A. Rimmer
    JLAB, Newport News, Virginia, USA
  • M.A. Kholopov, P. Vobly
    BINP SB RAS, Novosibirsk, Russia
  Funding: US DOE Office of Science, DE-FC02-07ER41499, DE-FG02-08ER85182; NERSC DOE contract No. DE-AC02-05CH11231.
Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron colliders. To verify the concept we conduct proof-of-the-principle experiment at RHIC. In this paper, we describe the current experimental setup to be installed into 2 o’clock RHIC interaction regions. We present current design, status of equipment acquisition and estimates for the expected beam parameters.
MOPPP088 Control of Nonlinear Dynamics by Active and Passive Methods for the NSLS-II Insertion Devices 759
  • J. Bengtsson, O.V. Chubar, C.A. Kitegi, T. Tanabe
    BNL, Upton, Long Island, New York, USA
  Funding: US DOE, Contract No. DE-AC02-98CH10886.
Nonlinear dynamics effects from insertion devices (IDs) are known to affect the electron beam quality of third generation synchrotron light sources. In particular, beam lifetime, dynamical aperture and injection efficiency. Methods to model the IDs' non-linear effects are known, e.g. by second-order (in the inverse electron energy) kick maps. Methods to compensate these effects are known as well, e.g. by first-order thin or thick magnetic kicks introduced by "magic fingers," "L-shims," or "current strips." However, due to physical or technological constraints, these corrections are typically only partial. Therefore, a precise model is required for a correct minimization of the residual nonlinear dynamics effects for the combined magnetic fields of the ID and compensating magnets. We outline a systematic approach for such predictions, based on 3D magnetic field and local trajectory calculation in the ID by the Radia code, and particle tracking by Tracy-3. The optimal geometry for the compensating magnets is determined from these simulations using a combination of linear algebra and genetic optimization.
MOPPP090 Spectral Performance of Segmented Adaptive-Gap In-Vacuum Undulators for Storage Rings 765
  • O.V. Chubar, J. Bengtsson, A. Blednykh, C.A. Kitegi, G. Rakowsky, T. Tanabe
    BNL, Upton, Long Island, New York, USA
  • J.A. Clarke
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  Funding: US DOE, Contract No. DE-AC02-98CH10886.
We propose an approach to the optimization of segmented in-vacuum undulators, in which different segments along an undulator may have different gaps and periods. This enables close matching between the gaps and the vertical "envelope" of electron beam motion in a storage ring straight section (carefully satisfying the associated vertical "stay clear" constraint) and, at the same time, precise tuning of all the segments to the same fundamental photon energy. Thanks to this, the vertical gaps in segments located closer to straight section center can be smaller than at extremities, and so the entire undulator structure can offer better magnetic performance, compared to the case of a standard undulator with constant gap (and period) over its length. We will present magnetic field, radiation flux, brightness and intensity calculation results for such segmented adaptive-gap in-vacuum undulators and demonstrate their gain in spectral performance over standard in-vacuum undulators, both for room-temperature and cryo-cooled realizations.
WEPPR098 Two Dimensional Impedance Analysis of Segmented IVU 3168
  • A. Blednykh, G. Bassi, J. Bengtsson, O.V. Chubar, C.A. Kitegi, T. Tanabe
    BNL, Upton, Long Island, New York, USA
  Funding: Work supported by DOE contract No: DE-AC02-98CH10886
Segmented Adaptive-Gap In-Vacuum Undulator (IVU) with variable magnetic gap along z-axis is considered as an alternative to the Constant Gap IVU (7mm gap) for the NSLS-II storage ring. The length of the Constant Gap IVU for a given minimum gap is limited by the beam stay clear aperture. With the new conceptual design of IVU the magnetic gap can be varied along z-axis and its minimum gap can be reduced down to 5.25mm in the center of the structure for the same stay clear aperture. Beam impedance becomes an important issue since the new design consists of several magnet gaps. Wakepotentials and impedances have been analyzed for a new type of IVU and the results compared with data for the reference geometry which is the Constant Gap IVU.